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Attribution of Chemistry-Climate Model Initiative (CCMI) ozone radiative flux bias from satellites

Kuai, Le and Bowman, Kevin W. and Miyazaki, Kazuyuki and Deushi, Makoto and Revell, Laura and Rozanov, Eugene and Paulot, Fabien and Strode, Sarah and Conley, Aandrew and Lamarque, Jean-Francois and Jöckel, Patrick and Plummer, David A. and Oman, Luke D. and Worden, Helen and Kulawik, Susan and Paynter, David and Stenke, Andrea and Kunze, Markus (2020) Attribution of Chemistry-Climate Model Initiative (CCMI) ozone radiative flux bias from satellites. Atmospheric Chemistry and Physics (ACP), 20 (1), pp. 281-301. Copernicus Publications. doi: 10.5194/acp-20-281-2020. ISSN 1680-7316.

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Official URL: https://www.atmos-chem-phys.net/20/281/2020/


The top-of-atmosphere (TOA) outgoing longwave flux over the 9.6 µm ozone band is a fundamental quantity for understanding chemistry–climate coupling. However, observed TOA fluxes are hard to estimate as they exhibit considerable variability in space and time that depend on the distributions of clouds, ozone (O3), water vapor (H2O), air temperature (Ta), and surface temperature (Ts). Benchmarking present-day fluxes and quantifying the relative influence of their drivers is the first step for estimating climate feedbacks from ozone radiative forcing and predicting radiative forcing evolution. To that end, we constructed observational instantaneous radiative kernels (IRKs) under clear-sky conditions, representing the sensitivities of the TOA flux in the 9.6 µm ozone band to the vertical distribution of geophysical variables, including O3, H2O, Ta, and Ts based upon the Aura Tropospheric Emission Spectrometer (TES) measurements. Applying these kernels to present-day simulations from the Chemistry-Climate Model Initiative (CCMI) project as compared to a 2006 reanalysis assimilating satellite observations, we show that the models have large differences in TOA flux, attributable to different geophysical variables. In particular, model simulations continue to diverge from observations in the tropics, as reported in previous studies of the Atmospheric Chemistry Climate Model Intercomparison Project (ACCMIP) simulations. The principal culprits are tropical middle and upper tropospheric ozone followed by tropical lower tropospheric H2O. Five models out of the eight studied here have TOA flux biases exceeding 100 mW m−2 attributable to tropospheric ozone bias. Another set of five models have flux biases over 50 mW m−2 due to H2O. On the other hand, Ta radiative bias is negligible in all models (no more than 30 mW m−2). We found that the atmospheric component (AM3) of the Geophysical Fluid Dynamics Laboratory (GFDL) general circulation model and Canadian Middle Atmosphere Model (CMAM) have the lowest TOA flux biases globally but are a result of cancellation of opposite biases due to different processes. Overall, the multi-model ensemble mean bias is −133±98  mW m−2, indicating that they are too atmospherically opaque due to trapping too much radiation in the atmosphere by overestimated tropical tropospheric O3 and H2O. Having too much O3 and H2O in the troposphere would have different impacts on the sensitivity of TOA flux to O3 and these competing effects add more uncertainties on the ozone radiative forcing. We find that the inter-model TOA outgoing longwave radiation (OLR) difference is well anti-correlated with their ozone band flux bias. This suggests that there is significant radiative compensation in the calculation of model outgoing longwave radiation.

Item URL in elib:https://elib.dlr.de/133324/
Document Type:Article
Title:Attribution of Chemistry-Climate Model Initiative (CCMI) ozone radiative flux bias from satellites
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Kuai, LeJPL, Pasadena, USAhttps://orcid.org/0000-0001-6406-1150
Bowman, Kevin W.JPL, Pasadena, USAUNSPECIFIED
Miyazaki, KazuyukiJPL, Pasadena, USAhttps://orcid.org/0000-0002-1466-4655
Deushi, MakotoMRI, Tsukuba, JapanUNSPECIFIED
Revell, LauraUniv. of Canterbury, Christchurch, Neuseelandhttps://orcid.org/0000-0002-8974-7703
Rozanov, EugenePMOD/WRC, Davos, SchweizUNSPECIFIED
Paulot, FabienNOAA, GFDL, Princeton, USAhttps://orcid.org/0000-0001-7534-4922
Strode, SarahNASA Goddard, Greenbelt, USAhttps://orcid.org/0000-0002-8103-1663
Conley, AandrewNCAR, Boulder, USAhttps://orcid.org/0000-0003-0061-9906
Lamarque, Jean-FrancoisNCAR, Boulder, USAhttps://orcid.org/0000-0002-4225-5074
Jöckel, PatrickDLR, IPAhttps://orcid.org/0000-0002-8964-1394
Plummer, David A.ECCC, Montreal, Kanadahttps://orcid.org/0000-0001-8087-3976
Oman, Luke D.NASA Goddard, Greenbelt, USAUNSPECIFIED
Worden, HelenNCAR, Boulder, USAhttps://orcid.org/0000-0002-5949-9307
Kulawik, SusanNASA Ames, Moffet Field, USAUNSPECIFIED
Paynter, DavidNOAA, GFDL, Princeton, USAhttps://orcid.org/0000-0002-7092-241X
Stenke, AndreaIAC, ETH Zürich, Schweizhttps://orcid.org/0000-0002-5916-4013
Kunze, MarkusFreie Univ., BerlinUNSPECIFIED
Date:8 January 2020
Journal or Publication Title:Atmospheric Chemistry and Physics (ACP)
Refereed publication:Yes
Open Access:Yes
Gold Open Access:Yes
In ISI Web of Science:Yes
Page Range:pp. 281-301
Publisher:Copernicus Publications
Keywords:CCMI, ESCiMo, MESSy, EMAC, ozone, radiative flux, satellite, chemiestry climate modelling, global modelling
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Earth Observation
DLR - Research theme (Project):R - Atmospheric and climate research, R - Project Climatic relevance of atmospheric tracer gases, aerosols and clouds
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics > Earth System Modelling
Deposited By: Jöckel, Dr. Patrick
Deposited On:08 Jan 2020 12:36
Last Modified:08 Jan 2020 12:37

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